[jira] [Created] (FLINK-28124) Flink on K8S in hosetNetwork mode, the CPU usage will spike

["liuzhuo (Jira)" <ji...@apache.org>]

liuzhuo created FLINK-28124:
-------------------------------

             Summary: Flink on K8S in hosetNetwork mode, the CPU usage will spike
                 Key: FLINK-28124
                 URL: https://issues.apache.org/jira/browse/FLINK-28124
             Project: Flink
          Issue Type: Bug
          Components: Deployment / Kubernetes, Runtime / Metrics
            Reporter: liuzhuo


When using the flink on k8s, in the configuration 'kubernetes. Hostnetwork. Enabled = true' parameters, If a node is running too many pods
, there will be a node CPU surge problem, The metric module collected the indicator information of the network card

 
{code:java}
Class :SystemResourcesCounter
Line 109 :calculateNetworkUsage(hardwareAbstractionLayer.getNetworkIFs());{code}
The problem is with this method
{code:java}
hardwareAbstractionLayer.getNetworkIFs(){code}
this method returns the current all the  network card on the machine, each pod will create a virtual network card (ifr_name = "kube - ipvs0"), In hostNetwork mode, the network card is visible to the public, resulting in too much network card information returned by the interface

For example, if a node runs 200 pods, then the method calling this interface in each POD will return at least 200 nic information. With the default execution once every 5 seconds, this machine needs to return 200*200=40000 network card information every 5 seconds, this results in a significant CPU consumption



--
This message was sent by Atlassian Jira
(v8.20.7#820007)